Apparatus for processing interrupts in microprocessing systems
First Claim
1. A data processor system comprising:
- a central processor including means for executing a sequence of instructions;
memory means for storing instructions and data;
a peripheral device including means for generating a peripheral device interrupt signal when communication between said central processor and said peripheral device is desired;
a common system bus connected to said central processor and said memory means;
control means connected to said common system bus for controlling said peripheral device;
said control means including means responsive to a peripheral device interrupt signal for placing an interrupt request signal on said common system bus, and means responsive to a bus grant signal on said common system bus for simultaneously placing the status and address of the peripheral device requesting an interrupt on said common system bus;
first means connected to said common system bus for generating a bus grant signal on said common system bus in response to an interrupt request signal thereon;
second means responsive to an interrupt request signal on said common system bus for generating a central processor interrupt signal;
an address register and a status register connected to said common system bus; and
,means responsive to said central processor interrupt signal for enabling said address and status registers to thereby load said address and status registers with the address and status of the peripheral device requesting the interrupt.
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Accused Products
Abstract
Circuitry external of a microprocessor determines priority between different peripheral devices requesting interrupts to generate a restart vector and a signal granting priority to one of the interrupt-requesting devices. The peripheral device loads its status and address into two addressable registers connected to a common system bus. The restart vector is loaded into the instruction register of the microprocessor. The microprocessor treats the restart vector as an instruction to store the contents of the program counter in memory and loads certain bits of the restart vector into the program counter. These bits represent the starting address of a subroutine of eight instructions for analyzing the interrupt. An interrupt is recognized and the status and identification of the interrupting device is stored in a single instruction cycle. On the next instruction cycle the first instruction of the interrupt analysis routine may begin. During this analysis routine the contents of the two addressable registers may be read out to determine which device caused the interrupt and what action should be taken in view of the status of the interrupting device. Provision is made for processing interrupts other than those requested by peripheral devices, and each type of interrupt generates a different restart vector thus selecting a different address as the first instruction address of the interrupt analysis routine.
112 Citations
11 Claims
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1. A data processor system comprising:
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a central processor including means for executing a sequence of instructions; memory means for storing instructions and data; a peripheral device including means for generating a peripheral device interrupt signal when communication between said central processor and said peripheral device is desired; a common system bus connected to said central processor and said memory means; control means connected to said common system bus for controlling said peripheral device; said control means including means responsive to a peripheral device interrupt signal for placing an interrupt request signal on said common system bus, and means responsive to a bus grant signal on said common system bus for simultaneously placing the status and address of the peripheral device requesting an interrupt on said common system bus; first means connected to said common system bus for generating a bus grant signal on said common system bus in response to an interrupt request signal thereon; second means responsive to an interrupt request signal on said common system bus for generating a central processor interrupt signal; an address register and a status register connected to said common system bus; and
,means responsive to said central processor interrupt signal for enabling said address and status registers to thereby load said address and status registers with the address and status of the peripheral device requesting the interrupt. - View Dependent Claims (2, 3, 4, 5)
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6. In a data processing system of the type having a central processor means connected by a common bus means to a plurality of access means, said access means selectively controlling access of a plurality of peripheral devices to said common bus means for the transfer of data between said peripheral devices and said common bus means, each said access means further including means responsive to a peripheral interrupt request for generating an interrupt request signal and means responsive to a bus grant signal for placing the address and status of the peripheral device making an interrupt request on said common bus means, the improvement comprising:
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priority encoder means responsive to interrupt request signals from said access means for applying a bus grant signal to the access means granted priority; means connected to said priority encoder means for generating a processor interrupt request signal in response to said interrupt request signals; means in said central processor responsive to said processor interrupt request signal for producing an interrupt acknowledge signal; restart vector generating means connected to said priority encoder means and responsive to said interrupt acknowledge signal for generating and applying a restart vector to said common bus means; first and second addressable registers connected to said common bus means for receiving and storing the status and address placed on the common bus means by the access means granted priority; and
,means responsive to said interrupt acknowledge signal for gating the status and address from the common bus means into said first and second addressable registers. - View Dependent Claims (7, 8, 9, 10, 11)
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Specification